Small credit-card-sized printed circuit (PC) memory cards that plug into slots in computer hardware have become standard in the industry, especially for portable computers. The Personal Computer Memory Card International Association (PCMCIA) develops and releases the "PC Card Standard" that defines parameters for PC memory cards. Cards and hardware developed by various manufacturers will be compatible if they are manufactured in conformance with the standard. Although the PCMCIA PC Card Standard may be periodically updated with new "Releases," a PC card assembly that conforms to any Release of the standard may generally be referred to in the art as a "PCMCIA PC Card assembly."
Release 2.0 of the PC Card Standard sets the size of extended version cards at 85.6 mm long and 54.0 mm wide. These dimensions correspond to the size of a standard credit card. Referring now to FIG. 1, there is shown an illustration of a standard PC Card 100. PC card 100 has a card guide first section 102, with a first standard thickness, and a second section 104 that is of a second standard thickness depending on the card type. For instance, second section 104 of a Type I card is 3.3 mm thick; a Type II card, such as is shown in FIG. 1, is 5 mm thick; and a Type III card is 10.5 mm thick. Some PC cards also include a battery 106, a write-protect switch 108, and a grounding clip 112. The standard also includes specifications for a 68-pin interface connector, mounting at connecting end 110, and the size of the slot in the hardware that receives the card.
The PC Card Standard includes minimum structural requirements for withstanding torque, bending, impact (drop), shock, vibration, warping, moisture, and other mechanical requirements. The cards are also required to meet standards for withstanding electromagnetic interference (EMI), radio frequency (RF) waves, and electrostatic discharge (ESD). These standards are usually met by enclosing the card in a protective metal cover. PC cards may also be required to meet standards set by the Joint Electronic Device Engineering Council (JEDEC), International Standards Organization (IPSO), and others.
The PC cards are used for flash memory, networking, modem connections to telephone systems, hard drives, cellular telephone connection, sound cards, and input/output (I/O) interface with other external peripheral hardware. Although laptop and palmtop systems are the primary users of PC cards, recent desktop systems have also incorporated card slots.
A number of assemblies comprising a card in its protective metal cover and conforming to the PCMCIA PC Card Standard are currently manufactured by a variety of suppliers. Such assemblies generically comprise a top cover and a bottom cover; the PC card is held between the top and bottom covers. Most of these covers require ultrasonic welding, laser welding, or adhesive bonding to adhere the components together. Such operations slow the assembly process, add cost, and introduce additional opportunities for error.
Many of these covers also require that the card be mounted in a special frame. Although it is known to make a cover assembly that snaps together, rather than being bonded, such snap-together covers have included special frames. Such frames are included either as a dielectric piece integrally molded into one of the metal covers or integral to a forged or die-cast, all-metal, unitary bottom cover.
The deficiencies of the conventional PC card assemblies show that a need still exists for an improved assembly. To overcome the shortcomings of the conventional assemblies, a new printed circuit card assembly is provided. An object of the present invention is to avoid processing steps such as ultrasonic welding, laser welding, and adhesive bonding. Another object is to provide a printed circuit card assembly that does not require an additional frame to hold the circuit board.